In the development of drip irrigation, it has become feasible to utilize a thinwall irrigation tube capable of being flattened and compactly rolled to minimize storage and shipping space as well as to be produced at a minimum cost. Such tubing, provided with extremely small drip openings is widely used; however, the problem of filtration to prevent clogging is a substantial one, and the service life is short. Also the rate of flow through such openings vary with pressure.
The present invention is directed to a means and method of installing emitters in such irrigation tubes; particularly emitters of the type which undergo momentary flushing at the beginning and the end of the irrigation cycle as well as to effect constant flow over a substantial pressure range. Such emitters being disclosed in a copending patent application Ser. No. 783,291. The present invention is summarized in the following objects:
First, to provide a means and method of installing emitters in an irrigation tube wherein a core assembly is received in the tube and is engaged externally through the walls of the tube so as to remain fixed in position while the tube is readily moved axially;
Second, to provide a means and method, as indicated in the preceding object wherein the core assembly and the structure surrounding the irrigation tube include novelly arranged pairs of internal and external rollers which provide minimal resistance to movement of the tube;
Third, to provide a means and method, as indicated said the preceeding objects, wherein the core assembly includes an anvil member and a fork member which may be disposed at different spacings and which cooperate respectively with an external cutting die to form perforations in the tube, and an external emitter inserting tool to effect proper placement of the emitters.